is it a rv cam ? or a racing cam? because that would be your diffrence and 35 with 3.55 gearing isnt going to help either

 

I think the pontiac has the cam and the dodge idles like it does lol. Could be a bad fuel pressure regulator letting to much fuel
by. I had a similar problem on 240sx i had. Is it hard to start? Also does the oil smell like gas?

 

not hard to start, and oil has a faint smell of gas, but i think its because it isnt getting a full burn.

 

I think your problem is the gears+tires and the cam. A cam with that type of lift is typically not made for towing. It's made for high RPM power. That coupled with the meat on those tires is causing a severe issue.

 

I don't think he has a cam in it, just using the reference for comparison


but ya I agree on the tires, when I read '35s with 3.55 gears', that instantly raised a flag.... although he says it's ok when not towing, but I think they play a big part in the problem (no pun intended)

 

Got a scanner? See if you can find out what temp the pcm thinks the engine is. I have seen this on GM vehicles when the sensor fails, the PCM thinks its -40 degrees.... so it DUMPS gas.

 

verify your fuel pressure.
and check all your sensors as of an obd scan tool
such as map volts, oxygen sensor volts, etc.

do you have any missfire?

 

no miss fires. The TPS has low voltage, so a TPS is going in it here in about 30 mins, keep shooting ideas out...
What is the easiest way to measure fuel pressure

 

with a fuel pressure gauge attached to the fuel rail

 

I don't think the 98 has the valve on the fuel rail.... I think that went away with the advent of the plastic fuel logs.... Need to get some assorted plumbing adapters to be able to hook up the gauge.